Solute distribution in the Ogallala Aquifer, Texas: lithium, fluoride, nitrate, chloride and bromide

• Autores: Paul F. Hudak
• Localización: Carbonates and Evaporites, ISSN 0891-2556, Vol. 31, Nº. 4, 2016, págs. 437-448
• Idioma: inglés
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• Resumen

  • Spatial patterns of lithium, fluoride, nitrate, chloride and bromide in the Ogallala Aquifer of northwestern Texas were mapped and evaluated. Solute concentrations and depths were compiled for 705 water wells sampled between 2008 and 2014. Lithium concentrations were high relative to typical groundwater; median and maximum concentrations were 66.8 and 2,790 ug/L, respectively. Almost half of the fluoride observations equaled or exceeded the secondary maximum contaminant level (MCL) of 2 mg/L. Many nitrate observations exceeded the MCL of 44.3 mg/L, and several chloride observations exceeded the secondary MCL of 250 mg/L, with a maximum concentration nearly ten times that level. Most bromide observations were less than 0.15 mg/L; however, some observations exceeded 10 mg/L. Several wells had high chloride/bromide ratios and high chloride concentrations. Generally, concentrations of all solutes were higher in the southern part of the aquifer, where wells are relatively shallow. Solute concentrations documented in this study are likely influenced by water–rock interaction within the aquifer, as well as mixing with groundwater in underlying bedrock containing evaporite minerals. Agricultural practices and possibly oilfield activity also affect water quality in the Ogallala Aquifer.